Cross-Site Request Forgery (CSRF) in firefly-iii/firefly-iii

Valid

Reported on

Nov 1st 2021


Description

Attacker is able to logout a user if a logged in user visits attacker website.

Impact

This vulnerability is capable of forging user to unintentional logout.

Test

Tested on Edge, firefox, chrome and safari.

Fix

You should use POST instead of GET/ANY.

To expand:

One way GET/ANY could be abused here is that a person (competitor perhaps:) placed an image tag with src="<your logout link>" ANYWHERE on the internet, and if a user of your site stumbles upon that page, he will be unknowingly logged out. This is why it should be a POST with a @csrf token.

Note

While this cannot harm a users account it can be a great annoyance and is considered a valid CSRF.

Occurences

We have contacted a member of the firefly-iii team and are waiting to hear back a month ago
James Cole validated this vulnerability a month ago
HDVinnie has been awarded the disclosure bounty
The fix bounty is now up for grabs
James Cole confirmed that a fix has been merged on 47fa9e 25 days ago
James Cole has been awarded the fix bounty
web.php#L84 has been validated